There is a need for simple coating methods to bind molecules on all types of materials whose pre-existing surface is not suitable for such applications. Molecules (such as peptides, proteins, polynucleotides, polycarbohydrates, drugs, dyes, labels, synthetic polymers and particles) attached to surfaces are used in many applications in life sciences research (such as drug discovery, diagnostics, imaging and drug delivery), as well as non-life science applications (such as electronics and catalysis), There are currently many approaches to forming such systems (e.g. those described in Hermanson, et al., Bioconjugate Techniques: Academic Press, 1996. and Sperling, R. A., Parak, W. J., “Surface modification, functionalization and bioconjugation of colloidal inorganic nanoparticles”, Phil. Trans. R. Soc A 368; 1333-1383, 2010).
The metal complexes described in WO 2006/002472 and WO 2011/140590 can be used to bind a variety of molecules to surfaces that have electron-donating species. Where the surfaces of the substrates used are hydrophobic (e.g. quantum dots, certain polymers, plastics and metals), they generally do not have electron-donating species (which tend to be associated with hydrophilic surfaces) and therefore need to be modified or treated in some way to generate more hydrophilic functionalities in order to actively bind molecules such as proteins, polynucleotides, etc. Without such treatments, passive binding to such hydrophobic surfaces commonly leads to denaturing and loss of functionality of many biological molecules, such as proteins.
However, existing treatment methods such as sputter coating, gamma or electron-beam irradiation, or plasma treatment are hard to control, require specialised equipment and do not have the potential of creating a diversity of different coatings. In addition, such techniques produce regions of differing hydrophobicities resulting in poor surface uniformity. Methods to form functional groups to covalently couple molecules on hydrophobic surfaces also have similar problems of poor surface uniformity.
It would be advantageous to have a method for attaching molecules to hydrophobic surfaces that is not labour-intensive, that does not require specialised equipment and that allows substrates to be produced that allow molecules to be attached in a uniform and/or controllable arrangement.
Reference to any prior art in the specification is not, and should not be taken as, an acknowledgment or any form of suggestion that this prior art forms part of the common general knowledge in any jurisdiction or that this prior art could reasonably be expected to be understood and regarded as relevant by a person skilled in the art.